Heating hydrocarbon fluids



Feb. 13, 1940.

w. E. LOBO HEATING HYDROCARBON FLUIDS Filed Oct. 30

IN V EN T OR. WALTER E L050 ATTORNEY WMLQ N Tl? m a 8 Q1 m MN 3 mm 8 v. 5 N w ooooooooooo oowoooeoooo o oeo oKooooooooeooo ooooomoooooooooooooo oo 0 00080000000 08000000 7 12,190, 35 HEATING HYDROCARBON-FLUIDS Walter E. Lobe, Westfield, N. 3., assignor to Gasoline Products (30., Inc., Newark, corporation of Delaware Application October so, 1934, Serial No. 750,617

' 12 Claims. cries- 51) This invention relates in general to the heating of hydrocarbon fluids and more especially toimprovements in the heating of hydrocarbon fluids in a controlled manner.

heatin of hydrocarbon fluids in a unitary heating apparatus having a plurality of separately flred combustion or radiant heating chambers and a common convection heating chamber receiving combustion gases from each of the combustion chambers.

' i The hydrocarbon fluid being heated may be initially divided into a plurality of streams and each stream passed through separate interconnected heat-absorbing tubes or conduit elements disposed in, the convection heating chamber wherein each stream of hydrocarbonfluid is separately preheated. The thus separately preheated streams may then be conducted separately through other interconnected heat-absorbing tubes or. conduit elements disposed in one of the combustion chambers in such a manner as to be heated preponderantly by radiant heat. Each ofthe streams of hydrocarbon fluid inpassing separately through tubes in the combustion chamber is heated to an elevated temperature, such as crackingtemperature, by the heat absorbed by said tubes from the combustion gases.

Subsequent to the heating of the separate streams of hydrocarbon fluid passing through the tubes in the mentioned combustion chamber, these streams are merged and then conducted through other heat-absorbing tubes or conduit elements disposed in another combustion chamher in such amanner as to be heated prepon-. derantly by radiant heat.

The thus-merged stream of ch in passingthrough the conduit elements in this combustion chamber is subjected to-additional heat therein so as to carry out the desired heating of said oil stream, as for example maintaining the hydrocarbon fluid at cracking temperature in this combustion chamben The invention will be more fullyunderstood from the following description taken inconjunction with the accompanying drawing in which:

. Figure l is anelevational view, partly in section, of a unitary furnace arrangement embody- Q ing my invention.

Figure 2 is a flow diagram in perspective, illustrating the flow of the plural streams of hydrocarbon fluid through one of the combustion chambers.

Referring to Figure 1, there is shown a furnace setting 9 divided into separate combustion or radiant heating chambers Z and 3 and a convec- This invention provides for the controlled tion heating chamber 4. The combustion cham- I bers 2 and 3 are separated from each other byan air-cooled bridge wall 5,and the combustion chamber 3 and the convection heating chamber 4 are separated from each other by anotheraircooled bridge wall 6. chambers2 and Bis preferably provided with an air-cooled. floor. As shown, the combustion chamber 2 has an air space. i therebelow and the combustion chamber ,3 has a similar air space 8' therebelow, the air passingthroughi these spaces cooling the floors of the respective cornbustion chambers to thereby prevent injury to the refractory material of the flooras wellas preventing excessive radiation of heat to the ground and being utilized, if desired, "as p reheated air for the burners used in conjunction;

the twoside walls of this chamber and the com-' j bustion chamber} is provided with a plurality of similarly positioned burners H. The number of burners for each of the combustion chambers may, of course, be varied depending on the duty which each combustion chamber is designed to fulfill. Moreover, while the burners have been shown as being horizontally disposed, they may be'positioned in the floor of the furnace and, therefore, extend vertically into each of the com bustion chambers. H

The hot products of combustion produced by the burners 9 in the combustion chamber 2 pass over the bridge wall 5 into the combustion chamher 3 where theyare combined with the hot products of combustion from the latter combustion chamber. These products, after passing in heat exchange with heat-absorbing tubes in the upper part or roof of the combustion chamber 3,pass over-the bridge wall 6 and areconducted through the convection heating chamber 4 to an outlet flue I2, from which they are conducted to a suitablelstack, not shown.

In carrying out 'myinvention in an apparatus of the type described,. one stream of oil, such as gasoline or naphtha to be reformed, or clean gas oil to be cracked, may be introduced into a line I3 and passed through a plurality of serially interconnected heat-absorbing tubes l4 occupying about one-half of the; space of theco'nvection heating chamber 4, as is indicated bythe irregular line AB. The stream of hydrocarbon fluid in passing through the tubes M is therein preheated and is conducted by means of a line 15 to a bridge wall coil section it composed of a Each of the combustion smrss PATENT orrics f l plurality of interconnected tubes disposed adjacent the lower part of the bridge wall 6. The hydrocarbon fluid passes through each of the tubes of the coil section I 6 as a continuous stream from which it is conducted to a four-wall coil section I'l extending around the two side walls and the bridge walls 5 and 6 which define the combustion chamber 3. As shown, more particularly in Figure 2, the hydrocarbon fluid upon entering the coil section I! is divided into parallel streams for passage through the four-wall coil section l1. From the four-wall coil section I! the stream of hydrocarbon fluid may be conducted by means of a line l8 to a coil section l9 composed of heat-absorbing tubes or conduit elements disposed upon the right half of theroof of the combustion chamber 3. The hydrocarbon fluid then flows in parallel streams through the tubes of the coil section l9 to an outlet line 28.

A second stream of hydrocarbon fluid, such as gasoline or naphtha to be reformed, or a clean gas oil to be cracked, may be introduced into a line 2| and passed through a plurality of seriallyinterconnected tubes 22 disposed in the other half of the convection heating chamber l as indicated by. the irregular line A-B. The hydrocarbon fluid in passing through the interconnected tubes 22 is therein preheated and is conducted by means of a line 23 to a bridge wall coil section 24in chamber 3 composed of heat-absorbing. tubes or conduit elements disposed adjacent the bridge wall 5 at the lower,

portion thereof. The hydrocarbon fluid flows through the tubes of the coil section 24 as a continuous stream and is conducted, as is more clearly shown in Figure 2, to a four-wall coil section 25 extending around the two side walls and the bridge walls 5 and 6. The tubes comprising the coil section 25, which are connected in parallel the same as the tubes of coil section I! occupy the spaces'between parallel connected groups of tubes forming the coil section [1. Thus, the hydrocarbon fluid passes through the coil section 25 in parallel streams and is conducted by means of a line 26 to a coil section 2'! composed of parallel connected tubes occupying the other half of the roof, the right-hand half being occupied by the coil section I9. the coil section 21 in parallel streams and merges with the other stream of hydrocarbon fluid passing through the coil section l9 in the line 28. The arrangement of tubes in the combustion chamber 3 and. the flow of hydrocarbon fluid therethrough' may be clearly seen from an inspection of Figure 2, the coil sections l6, l1 and I9, together with the connections therebetween being indicated by dash lines, while the other coil sections are indicated by solid lines.

Figure 2 shows vertical lines connecting parallel connected tubes at the junctions of the walls of the furnace setting. This indicates that two parallel streams enter a header, pass through the single passage therein and leave as two The hydrocarbon fluid passes through tubes connected for parallel flow and spaced from the roof of the combustion chamber 2. From the roof section 29, the hydrocarbon fluid is conducted through a line ill to a coil section 32 composed of a plurality of tubes also connected for parallel flow and disposed adjacent the bridge wall but spaced therefrom. The hydrocarbon fluid is then passed by means of a line 33 to a coil section 3 3 composed of a plurality of tubes similarly connected and spaced from the end wall, thence through a line 35 to a similar side wall coil section 36 disposed in the space between the coil section 34 and the end Wall, the tubes of the two coil sections being arranged in staggered relation with each other. From the coil section 36 the hydrocarbon fluid may be conducted through a line 3'! to another similar coil section 38 disposed in the space between the bridge wall 5 and the coil section 32, the tubes of the two coil sections also being arranged in staggered relation with each other. The hydrocarbon fluid after passing throughthe coil section 38 is conducted by means of a line 39 to an upper coil section 4| disposed in the space between the roof of the combustion chamber 2 and the coil section 29, the tubes of the two coil sections also being in a staggered relation with each other. The hydrocarbon fluid after passing through the roof section 4| is conducted by means of a transfer line 42 to suitable other equipment, such as an evaporator or the like, for further treatment.

All of the tubes disposed within the combustion chamber 2 are connected for providing parallel flow of the stream of hydrocarbon fluid passing therethrough. As shown, the tubes forming the individual coil sections are connected for conveying two parallel streams of hydrocarbon fluid therethrough.

The tubes in the combustion chamber 2 are adapted to act as a soaking section for the merged stream of hydrocarbon fluid passing therethrough. Thus, the hydrocarbon fluid at cracking temperature introduced into the roof tubes 29 may be maintained at cracking temperature or slightly elevated in temperature in its passage through the various coil sections in the manner described. Clearly by regulating the extent of firing of the burners 9 associated with the combustion chamber 2, excellent control of the amount of heat imparted to the hydrocarbon fluid passing through the tubes in the combustion chamber 2 is made possible.

While the tubes in the various sections of the furnace have been shown as connected in a certain manner, it is to be clearly understood that such connections may be varied with more or fewer parallel paths, as the case may be, being provided by connecting more or fewer of the tubes in parallel or, if desired, a single continuous path may be provided for the hydrocarbon fluid being heated in the manner described. It is also to be understood that the direction of flow of oil through the various coil sections may be varied, as desired, as well as the positioning of the tubes in the various chambers.

' While the convection heating chamber 4 has been shown as positioned to the right of both of the combustion'chambers 2 and 3, it is also to be clearly understood that this convection heating chamber may be disposed between the combustion chambers 2 and 3 and separated walls thus forming the convection heating chamber.

The coil sectionsdisposed adjacent the roof in each of the combustion chambers are, like the wall coil sections, heated preponderantly by radiant heat. These coil sections, however, may receive some convective heat from the combustion gases, those in the combustion chamber '3 receiving some convective 'heatfrom the combustion gases from both combustion chambers.

Obviously, many modifications'in the apparatus and mode of operation may be made without departing from the spirit of the invention which is defined in its true scope in the appended claims.

I claim:

1. The method of heating-apluralityof streams of hydrocarbon fluid to elevated temperature in a heating apparatus havinga plurality of separately fired heating zones and a separate convection heating zone receiving hot gases from each of said fired heating zones which comprises passing hydrocarbon fluid in separate streams through the convection heating zone and therein subjecting them separately to the convection heat of said combustion gases, separately passing the thus-heated streams through one of the separately fired heating zones from p the point where each of said streams enters said last mentioned separately fired heating zone to a point where each leaves said last mentioned separately fired heating zone, and therein separately heating each stream, preponderantly by radiant heat, to elevated temperature, thereafter combining each of said separately heated streams of fluid and passing the thus-combined stream through another separately fired heating zone wherein it is subjected ,to additional heat, preponderantly radiant heat." i i 2. The method of heating a plurality of streams of hydrocarbon oil in a heating apparatus having a plurality of separately fired'heating zones defined by walls and a roof and a convection heating zone receiving hot gases irom-each'of said fired heating zones which comprises passing hydrocarbon oil in separate streams through conduit elements in said convection heating zone and therein subjecting each stream to convection heat absorbed by said conduit elements,

through conduit elements in another-separately fired heating zone wherein it is additional heat.

3. The method of heating a plurality of streams of hydrocarbon oil in a heating apparatus having a plurality of separately fired heating zones subjected to defined by walls and a roof and a convection' heatingzone receiving hot gases from each of said fired heatingzones which comprises passing hydrocarbon oil in separate streams through conduit elements in said convection heating zone and therein subjecting eachstream to convection heat absorbed by said conduit elements, separately passing the thus-heated streams of oil 'throug'h other sseparateconduit elements along in:

certain of the vertical walls of one of the separately fired heating zones-from the point where each of said streams enters said conduit elements along the walls to a point where each stream leaves said zone and therein separately heating each Stream, preponderantly by radiant heat, to elevatedtemperature, thereafter combining each of said separately heated streams of oil and passing, the thus-combined stream,

through conduit elements along certain of the vertical walls of another'separately fired heat- 7 ing zone -=whe1'ein it is subjected to additional heat.

;'4. The method of heating a plurality of streams of hydrocarbon oil in a heating apparatus having a plurality of separately fired heating zones definedby walls and a'roof, and a convection heatingzone receiving hot gasesfrom eac'h'of -said fired heating zones'which comprises passing hydrocarbon oil in separate streams through conduit elements in said convection yheatin'g zone and therein subjecting each stream to convection heat absorbed by said conduit ele ments, separately passing the thus-heated streams of oil through other separate conduit elements along certain ofthe vertical walls of one of the separately fired heating zones and therein separately heating each stream, prepondera'ntly-by radiant heat, to elevated temperature, separately passing each of said streams from the conduit elements along certain of said walls of said separately fired heating zone to and through separate conduit elements on the roof thereof, thereafter combining each of said separately heated streams of oil and passing the thus-combined stream through conduit elements in another separately fired heating zone wherein it is subjected to additional heat.

5. The method of heating a plurality of streams of hydrocarbon oil in a heating appaheat, to elevated temperature, separately passing each of said :streams, from the conduit elements along said walls. of said separately fired heating zone to and through separate conduit elements on the roof thereof, thereafter combining each of said separately heated streams of oil and passing the thus-combined stream through conduit elements along vertical walls of another separately fired heating zone wherein it is subjected to additional heat.

6, The method of heating a plurality of streams of hydrocarbon oil in a heating apparatus having a plurality of separately fired heating zones defined by walls and a roof, and a convection heating zone receiving hot gases from each of said fired heating zones which com-,

prises passing hydrocarbon oil in separate streams through conduit elements in said convection heating zone and therein subjecting each streamv to convection heat absorbed by said conduit elements, separately passing the thus-heated streams of oil through other separate conduit elements along the walls of i one of the separately fired heating zones and therein separately heating each stream, preponderantly by radiant heat, to elevated temperature, separately passing each of said streams from the conduit elements along the walls of said separately fired heating zone to and through separate conduit elements on the roof thereof, thereafter combining each of said separately heated streams of oil and passing the thus-combined stream through conduit elements along the walls of another separately fired heating zone and therein subjecting it :to additional heat, preponderantly radiant heat, absorbed by said conduit elements and then passing said stream through other conduit elements on the roof of the last-mentioned heating zone.

'7. The method in accordance with claim 6 in which the separate streams of oil passing through the first-mentioned separately fired heating zone are raised to cracking temperature and there after maintained at cracking temperature in their passage as a single stream through the second-mentioned separately fired heating zone.

8. An apparatus adapted for heating hydrocarbon fluids which includes a plurality of combustion chambers, separate means for producing hot products of combustion for each combustion chamber, a conduit element disposed in each of said combustion chambers to be heated preponderantly by radiant heat, said conduit element in one of said combustion chambers being arranged along certain of the vertical walls and roof thereof and connected for conveying a plurality of separate streams of hydrocarbon fluid from the point where each stream enters said combustion chamber to a point where each stream leaves said combustion chamber, and means whereby the plurality of streams of hydrocarbon fiuid are merged and conducted as a single merged stream through said conduit. ele ment in another of said combustion chambers.

9. An apparatus adapted for heating hydrocarbon fluids which includes a plurality of combustion chambers, separate means for producing hot products of combustion for each combustion chamber, a conduit element disposed, in each of said combustion chambers to be heated preponderantly by radiant heat, said conduit element in one of said combustion chambers being arranged along certain of the vertical walls and roof thereof and connected for conveying a plurality of separate streams of hydrocarbon fiuid from the point where each stream enters said combustion chamber to a point where each stream leaves said combustion chamber,

and means whereby the plurality of streams of hydrocarbon fluid are merged and conducted as a single merged stream through said conduit element in another of said combustion chambers, said conduit element in said lastmentioned combustion chamber being arranged along certain vertical walls and the roof of said last mentioned combustion chamber.

10. The method of heating a plurality of streams of hydrocarbon fluid to elevated temperature in a heating apparatus having a plurality of separately fired heating zones and a separate convection heating zone receiving hot gases from each of said fired heating zones which comprises passing hydrocarbon fluid in separate streams through the convection heating zone and therein subjecting them separately to the convection heat of said combustion gases, separately passing the thus-heated streams through one of the separately fired heating zones and therein separately heating eachstream, preponderantly by radiant heat, to elevated temperature, thereafter combining each of said separately heated streams of fluid and passing the thus-combined stream through banks of heater tubes arranged along certain vertical walls and the roof in another separately fired heating zone wherein it is subjected to additional heat, said combined stream being passed through heater tubes exposed to direct radiant heat and then through shielded heater tubes in said last mentioned heating, zone.

11. The method of heating a plurality of streams of hydrocarbon oil to elevated temperature which comprises passing hydrocarbon oil inseparate streams of restricted cross-sectional area through a separately fired heating zone from the point where each of said streams enters said zone to a point Where each leaves said zone, and therein separately heating each stream, preponderantly by radiant heat, to cracking temperature, thereafter combining said separately heated streams of oil and passing the thus combined stream through banks of tubes arranged adjacent certain vertical walls of another separately fired heating zone and therein subjecting the stream to additional heat, preponderantly radiant heat, to maintain the stream at cracking temperature.

12. The method of heating a plurality of streams of hydrocarbon oil to elevated temperature which comprises passing hydrocarbon oil in separate streams of restricted cross-sectional area through a separately fired heating zone from the point where each of said streams enters said zone to a point where each leaves said zone, and

therein separately heating each stream, preponderantly by radiant heat, to cracking temperature, thereafter combining said separately heated streams of oil and passing the thus combined stream through banks of heater tubes arranged along certain boundary surfaces in another separately fired heating zone wherein it is subjected to additional heat, the combined stream being first passed through heater tubes exposed to direct radiant heat and then through shielded heater tubes in said last mentioned separately fired heating zone.

WALTER E. LOBO. 

